currently it's locked behind _MSC_VER, but anything that runs on Win32
should be able to use those functions as long as it has something that
can pass as a debug window.
also, add a non-wildcard-accepting version of showdebug for the dumpit()
functions in dungeon.c and questpgr.c; this makes DEBUGFILES=* workable
without being excruciatingly painful
VS2013 _really_ doesn't like having shared directories for
any sort of intermediate files, and will generate a nice little
pile of useless warnings as a result.
Mostly it's just project formats, but VS2013 does require
parallel compilation to be turned off and synchronous
PDB writes to be turned on (since we reuse intermediate
output directories).
Cleaning that up is for some time in the future.
